For the Filling:
Melt the butter and marshmallow cream in the microwave, about 30-60 seconds, until the butter is fully melted.
In a large mixing bowl, combine the melted butter and marshmallow with the powdered sugar and vanilla. Cream together until just blended.
Drop onto a silpat (or large piece of parchment paper). Use your hands to knead the “dough” into a large ball.
Divide the ball into 6 equal portions. Roll each portion into a 7-8-inch log, maintaining a 1-inch thickness.
Wrap each log in parchment paper and freeze for two hours until firm.
For the Coating:
Melt caramel bits and butter in an 11×7-inch baking dish in the microwave, about 1 1/2 minutes, until smooth. The mixture will be thick, and the butter may separate; this is okay.
Allow the caramel to cool slightly, then using your hands, mix the butter back into the caramel and press the mixture into the bottom of the baking dish. Score into 6 equal portions.
To cover the marshmallow centers, unwrap the frozen log and use your hands to spread one section of caramel over the center completely.
Once the log is fully covered, press the chopped peanuts into the caramel. Re-wrap in parchment paper and refrigerate. Repeat for each log.
When ready to enjoy, slice each log into 1-inch pieces.